CVE-2026-21855 Tarkov Data Manager has Unauthenticated Reflected XSS
Attackers can execute arbitrary JavaScript in victims' browsers via malicious URLs in the Tarkov Data Manager toast notification system.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-21855?
CVE-2026-21855 is a critical cross-site scripting vulnerability in the-hideout tarkov-data-manager, published on 7 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
The Tarkov Data Manager is a tool to manage the Tarkov item data. Prior to 02 January 2025, a reflected Cross Site Scripting (XSS) vulnerability in the toast notification system allows any attacker to execute arbitrary JavaScript in the context of a victim's browser session by crafting a malicious URL. A series of fix commits on 02 January 2025 fixed this and other vulnerabilities.
Weakness: CWE-79
Which versions are affected by CVE-2026-21855?
It affects 1 product.
Products include Tarkov Tarkov Data Manager.
How do I fix CVE-2026-21855?
No fix has been published for CVE-2026-21855 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-21855 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21855 exists.